//===--- SourceExtraction.cpp - Clang refactoring library -----------------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#include "clang/Tooling/Refactoring/Extract/SourceExtraction.h"

#include "clang/AST/Stmt.h"

#include "clang/AST/StmtCXX.h"

#include "clang/AST/StmtObjC.h"

#include "clang/Basic/SourceManager.h"

#include "clang/Lex/Lexer.h"

using namespace clang;

namespace {

/// Returns true if the token at the given location is a semicolon.

bool isSemicolonAtLocation(SourceLocation TokenLoc, const SourceManager &SM,

                           const LangOptions &LangOpts) {

  return Lexer::getSourceText(

             CharSourceRange::getTokenRange(TokenLoc, TokenLoc), SM,

             LangOpts) == ";";

}

/// Returns true if there should be a semicolon after the given statement.

bool isSemicolonRequiredAfter(const Stmt *S) {

  if (isa<CompoundStmt>(S))

    return false;

  if (const auto *If = dyn_cast<IfStmt>(S))

    return isSemicolonRequiredAfter(If->getElse() ? 
If->getElse()0

                                                  : If->getThen());

  if (const auto *While = dyn_cast<WhileStmt>(S))

    return isSemicolonRequiredAfter(While->getBody());

  if (const auto *For = dyn_cast<ForStmt>(S))

    return isSemicolonRequiredAfter(For->getBody());

  if (const auto *CXXFor = dyn_cast<CXXForRangeStmt>(S))

    return isSemicolonRequiredAfter(CXXFor->getBody());

  if (const auto *ObjCFor = dyn_cast<ObjCForCollectionStmt>(S))

    return isSemicolonRequiredAfter(ObjCFor->getBody());

  if(const auto *Switch = dyn_cast<SwitchStmt>(S))

    return isSemicolonRequiredAfter(Switch->getBody());

  if(const auto *Case = dyn_cast<SwitchCase>(S))

    return isSemicolonRequiredAfter(Case->getSubStmt());

  switch (S->getStmtClass()) {

  case Stmt::DeclStmtClass:

  case Stmt::CXXTryStmtClass:

  case Stmt::ObjCAtSynchronizedStmtClass:

  case Stmt::ObjCAutoreleasePoolStmtClass:

  case Stmt::ObjCAtTryStmtClass:

    return false;

  default:

    return true;

  }

}

/// Returns true if the two source locations are on the same line.

bool areOnSameLine(SourceLocation Loc1, SourceLocation Loc2,

                   const SourceManager &SM) {

  return !Loc1.isMacroID() && !Loc2.isMacroID() &&

         SM.getSpellingLineNumber(Loc1) == SM.getSpellingLineNumber(Loc2);

}

} // end anonymous namespace

namespace clang {

namespace tooling {

ExtractionSemicolonPolicy

ExtractionSemicolonPolicy::compute(const Stmt *S, SourceRange &ExtractedRange,

                                   const SourceManager &SM,

                                   const LangOptions &LangOpts) {

  auto neededInExtractedFunction = []() {

    return ExtractionSemicolonPolicy(true, false);

  };

  auto neededInOriginalFunction = []() {

    return ExtractionSemicolonPolicy(false, true);

  };

  /// The extracted expression should be terminated with a ';'. The call to

  /// the extracted function will replace this expression, so it won't need

  /// a terminating ';'.

  if (isa<Expr>(S))

    return neededInExtractedFunction();

  /// Some statements don't need to be terminated with ';'. The call to the

  /// extracted function will be a standalone statement, so it should be

  /// terminated with a ';'.

  bool NeedsSemi = isSemicolonRequiredAfter(S);

  if (!NeedsSemi)

    return neededInOriginalFunction();

  /// Some statements might end at ';'. The extraction will move that ';', so

  /// the call to the extracted function should be terminated with a ';'.

  SourceLocation End = ExtractedRange.getEnd();

  if (isSemicolonAtLocation(End, SM, LangOpts))

    return neededInOriginalFunction();

  /// Other statements should generally have a trailing ';'. We can try to find

  /// it and move it together it with the extracted code.

  Optional<Token> NextToken = Lexer::findNextToken(End, SM, LangOpts);

  if (NextToken && NextToken->is(tok::semi) &&

      areOnSameLine(NextToken->getLocation(), End, SM)) {

    ExtractedRange.setEnd(NextToken->getLocation());

    return neededInOriginalFunction();

  }

  /// Otherwise insert semicolons in both places.

  return ExtractionSemicolonPolicy(true, true);

}

} // end namespace tooling

} // end namespace clang